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(No Model.)

0. W. BROWN.- PLUG FOR ESTABLISHING ELEUTRIGAL GONNEGTIONS.

No. 528,529. Patented Nov. 6, 1894.

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UNITED- STATES PATENT OFFICE,

CHARLES W. BROWN, OF MONTREAL, CAN ADA, ASSIGNOR TO THE BELL TELE- PHONE OOMPANY OF CANADA, LIMITED, OF SAME PLACE.

P LUG FOR ESTABLISHING ELECTRICAL CONNECTIONS.

SPECIFI CATION forming part Of Letters Patent NO. 528,529, dated November 6, 1894- Applioation filed January 16, 1894. Serial No. 497,112- (No model.)

.To all whom it may concern:

Be it known that I, CHARLES WARREN BROWN, of the city of Montreal, in the District of Montreal and Province of Quebec, Canada, have invented certain new and useful Improvements in Plugs for Establishing Electrical Connections; and I do hereby desequences of which are interference with the proper transmission of current and considerable trouble and expense in removing and replacing parts.

The object of the invention is to avoid the objections just mentioned and to insure a proper contact of the plug at all times, as well as incidentally to render possible the ready removal of any accumulation of dust or foreign matter by simply rotating the plug in the socket.

The invention consists in constructing the part of the plug which enters the socket, with one or more flexible sections or expanders adapted to hold the plug firmly in proper position to effect a perfect connection between it and the socket.

For full comprehension however of themvention, reference must be had to the annexed drawings, forming a part of this specification, in which like symbols indicate corresponding parts, and wherein- Figure 1 is a side view of a telephone switchboard plug with insulated handle, sleeve or cover portion removed; Fig. 2 another side view enlarged of the forward half of plug taken at right angles to that of Fig. 1 the insulated handle portion being in place and shown partly in section, and Fig. 3, a transverse section on line 00 00 Fig. 2.

The plug which I have chosen to illustrate the application of my invention, is one composed of the metallic core piece or stem a, cut

away at the rear part to receive the usual cord ends and connections, all of which are inclosed by the insulated handle-sleeve or cover I) and hollowed through the forward portion 0 c 0, part of which enters the socket of the switch board, to carry the metallic top extension 0 and its insulating sleeve d. In order that the parts lettered o 0' shall always remain firmly in place in the socket (indicated by dotted lines in Fig. 2) I expand the diameter thereof preferably by cutting slits e e extending longitudinally forward from the rear end of the hollowed portion 0 c c to Within a short distance of its forward end so that the section fbetween such slits being sufficiently thin can be forced laterally outward and constitute'a flexible section or expander normally projecting beyond the periphery of the part c c, the function of which will be to effect a tight fitting of the plug within the socket and the preventing of any tilting of same notwithstanding any enlargement of the socket through wear.

An additional function of the flexible section is its action as a reamer or scraper when the plug is rotated in the socket for the removal of dust, &sc.,this being effected through the lateral projection of the section beyond the periphery of the part c c.

As the handle sleeve b projects some little distance over the rear end of the forward hollowed portion 0 so as to prevent the rear end of the expander being completely bent outward in any accidental way it is necessary to cutaway either an inner portion ofthe sleeve b or to reduce the rear end of the expander section as shown at g which latter method is preferred, in order that the lateral projection of the expander to the desired distance will not be prevented by such sleeve b.

What I claim is as follows:

1. A plug for establishing electrical connections having a bodyportion tubular in cross section, to be inserted in a correspondin 'ly shaped socket, and having one or more integral flexible expanders normally projecting beyond the periphery of the tubular body portion for the purpose set forth.

2. A plug for establishing electrical connections having a body portion tubular in cross section, to be inserted in a correspond ingly shaped socket, and having one or more integral flexible expanders normally projecting in an inclined position beyond the periphery of the tubular body portion for the purpose setforth.

3. A plug for establishing electrical connections, having a metallic forward body portion tubular in cross section adapted to be inserted in a correspondingly shaped socket and one or more flexible sections or expanders integral with and normally projecting beyond the periphery of said body portion, in increasing lateral expansion rearward for the purpose set forth.

4. A plug for establishing electrical connections, having a metallic body portion, tubular in cross section adapted to be inserted in a correspondingly shaped socket and one or more flexible sections or expanders integral with said body portion normally projecting beyond the periphery thereof and formed by slits in same.

5. A plug for establishing electrical connections having a metallic forward body portion tubular in cross section adapted to be inserted in a correspondingly shaped socket, one or more flexible sections or expanders integral with said forward body portion formed by slits extending from the rear of said body portion toward its forward end and an insulated handle sleeve extending over the rear end of such forward body portion for the purpose set forth.

6. A plug for establishing electrical connections, having a metallic body portion, tubularin cross section adapted to be inserted in a correspondingly shaped socket and one or more integral flexible sections or expanders extendingin an inclined position longitudinally of such body for the purpose set forth.

7. A plug for establishing electrical connections, having a metallic forward body portion, tubular in cross section adapted to be inserted in a correspondingly shaped socket, one or more flexible sections or expanders integral with said forward body portion formed by slits extending from the rear of said body portion toward its forward end, the rear end or ends ofsuch flexible expander or expanders being reduced in thickness, and an insulated handle sleeve having its forward end extending over such reduced ends for the purpose set forth Montreal, January 6, 1894.

CHARLES W. BROWVN.

In presence of- FRED. J. SEARS, R. A. O. KIMBLE. 

